


        function scrollLetter(){
            if($('.news>span').css('display') == 'none') return false;     
            var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
            var scrollHeight = document.documentElement.scrollHeight || document.body.scrollHeight;
            var footH = $('footer')[0].offsetHeight;
            var needScroll = scrollHeight - window.innerHeight;
            var marginTopMax = scrollHeight - originalItemTop - originalScrollTop - $('.news>span')[0].offsetWidth - footH;
            var marginVal = (scrollTop / needScroll) * marginTopMax + 'px';
            $('.news>span')[0].style.marginTop = marginVal;
        }
        var originalItemTop = $('.news>span')[0].getBoundingClientRect().top;
        var originalScrollTop = document.documentElement.scrollTop || document.body.scrollTop;
        $(document).ready(function(){
            scrollLetter();
            $(window).scroll(function(){
                scrollLetter();
            })
        })